Firstly some definitions to give my post clarity. Obviously these are my personal definitions.
Ethical Non Monogamy - Relationships that have the potential of the people involved having multiple sexual and/or romantic relationships with the informed consent of all the people involved.
Open relationship - a relationship where one or more of the people who are romantically committed to each other only have or can have sexually focused relationships outside of their union.
Poly relationship - a relationship where one or more of the people who are romantically committed to each other have or can have sexual and/or romantic relationships outside of that union. It does not have the limitations on emotional availability outside of the union that open relationships have.
DADT - same definition as NYCindie. It's a relationship where the people involved are expected to completely conceal that they are not monogamous. Failure to do this would be a breach of consent.
Because I believe that polyamorous relationships do not have restrictions on emotional availability outside of the primary relationship, I can't see relationships that have a DADT agreement (as I defined it) as polyamorous. Unless you are able to speak about your other partners and although they don't have to be best friends, have all your partners in the same room for an important event in their hinge's life, I can't see how the emotional availability and opportunity to bond romantically can be unrestricted. Relationships with a DADT can only be open relationships by my definitions. I have no issue with any form of ethical and consensual non monogamy but that arrangement is not something that I could accept from a partner and nor could I enter a romantic relationship where my potential partner has that agreement with an existing partner. I might be happy to have a more casual arrangement with them.